Donohue T M, Hofert J F, Zetterman R K
Liver Study Unit, Veterans Administration Medical Center, Omaha, Nebraska.
Biochem Biophys Res Commun. 1988 Sep 30;155(3):1471-7. doi: 10.1016/s0006-291x(88)81307-x.
The present study was conducted to examine the nature of the increase in tyrosine aminotransferase (TAT) activity by acute ethanol administration. A significant rise in aminotransferase activity was observed as early as 1 hr after intact rats were gavaged with ethanol. Ethanol administration also increased TAT activity in adrenalectomized rats. Inhibition of ethanol metabolism by pyrazole administration had no effect on the ethanol-induced increase in TAT activity. Immunochemical analyses revealed that the enhancement of TAT activity in ethanol-fed rats correlated with an increase in aminotransferase protein. Measurement of the rate of TAT synthesis showed that in ethanol-fed rats, [3H]leucine was incorporated into the aminotransferase protein at a higher rate than in controls by a factor which was similar to the enhancement in enzyme activity. Our findings indicate that an acceleration of TAT synthesis fully accounts for the increase in TAT activity during the early stage of enzyme induction. TAT induction by ethanol administration is not dependent upon an increase in adrenal corticosteroid production, nor does it require ethanol metabolism.
本研究旨在探讨急性给予乙醇后酪氨酸转氨酶（TAT）活性增加的本质。在用乙醇灌胃完整大鼠后，早在1小时就观察到转氨酶活性显著升高。给予乙醇也会增加肾上腺切除大鼠的TAT活性。给予吡唑抑制乙醇代谢对乙醇诱导的TAT活性增加没有影响。免疫化学分析显示，乙醇喂养大鼠中TAT活性的增强与转氨酶蛋白的增加相关。TAT合成速率的测量表明，在乙醇喂养的大鼠中，[3H]亮氨酸掺入转氨酶蛋白的速率比对照组高，其倍数与酶活性的增强相似。我们的研究结果表明，TAT合成的加速完全解释了酶诱导早期TAT活性的增加。乙醇给药诱导TAT并不依赖于肾上腺皮质类固醇生成的增加，也不需要乙醇代谢。
